#include <bits/stdc++.h>
#define cin fin
#define cout fout
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");
bool viz[100008];
vector<int>v[100008];
int st,dr,a,b,i,n,m,x,nod,cc,j,cnt;
void DFS(int n)
{
    viz[n]=1;
    cnt++;
    for(auto i:v[n])
    {
        if(viz[i]==0)
            DFS(i);
    }
}
int main()
{
    cin>>n>>m;
    for(i=1;i<=n;i++)
    {
       cin>>a>>b;
       v[a].push_back(b);
       v[b].push_back(a);
    }
    cc=0;
    for(i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            cc++;
            DFS(i);
        }
    }
    cout<<cc<<'\n';
    return 0;
}